Jay, the Cooling chapters are in Section 20. Unfortunately, the Model 124 Version 1.0 CD-rom (blue in color) has some problems in it and the html index pages don't always show all of the sections. You can do one of two things: just go into the directory folders of the CD and find the Section 20 pdf files (CD/Program/Engine/103 or 104....then look at all the 20-xxxx pdf files until you find what you want (oprn directly with Acrobat Reader). Or you can call 1-800-ask-mercedes and ask for the tech pub dept, explain your problem and they should send you the Version 1.1 CD set (black in color) in the mail, free of charge.
Hope this helps.